SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f969b81600c77436b31ad8f617169b1518696d1eb79e9ba31d0855c6a6ecab2' 
  AND token = 'l02UsPNy48p+qpcfTLjpF4ik0YwecC8DXTVBplc8x4I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}